JPS6224894Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a piezoelectric switch that uses a polymer piezoelectric film with electrodes on both sides and uses an electric signal obtained by displacing the polymer piezoelectric film as an input signal, and particularly The purpose is to provide a device that gives a sense of moderation during operation and can be made thinner.

In general, electrodes are provided on both sides of a piezoelectric film of a piezoelectric polymer such as polyvinyl fluoride, polyvinylidene fluoride, polyvinyl chloride, polyvinylidene chloride, nylon 11, natron 12, polycarbonate, polymethyl methacrylate, etc. It is well known that by applying stress to a film and causing it to displace, an electrical signal such as voltage or current appears between electrodes.

A piezoelectric switch using such a polymer piezoelectric film was constructed as shown in FIGS. 1 and 2.

First, as shown in FIG. 1, a plate spring 3 made of an elastic metal plate formed in a dome shape is arranged on a substrate 2 with a recess 1 formed on the upper surface, and a polymer plate spring 3 with electrodes on both sides is placed on top of the plate spring 3. A piezoelectric film 4 is disposed, an insulating protective sheet 5 is disposed on the upper surface of the polymer piezoelectric film 4, and a housing 7 having an operating window 6 is disposed on the protective sheet 5. Ta.

This configuration does not use a keytop, so
Although it is possible to make it thinner, it requires the housing 7, so it cannot be made sufficiently thin, and if this product is used as a keyboard switch for an electronic desktop calculator, a display is required on each piezoelectric switch. However, there were drawbacks such as the need to separately provide this display.

Furthermore, in the one shown in FIG. 2, a polymer piezoelectric film 4 having electrodes on both sides is arranged on a substrate 2 having a recess 1 on the upper surface, and a guide plate 8 is placed on the substrate 2 at a predetermined interval. A housing 7 is disposed, and a key top 10, which is constantly urged upward by a spring 9, is disposed between the guide plate 8 and the housing 7, and the key top 10 is pressed against the spring 9 to provide a guide. It is configured to apply stress to the polymer piezoelectric film 3 at the lower end of the key top 10 projecting downward from the plate 8 to obtain an electrical signal.

According to this configuration, the key top 10 and the vertical stroke of the key top 10 become thicker, making it extremely difficult to reduce the thickness of the key top 10.

The present invention eliminates the above-mentioned drawbacks of the prior art.

Embodiments of the present invention will be described below with reference to FIGS. 3 and 4.

Reference numeral 11 denotes a substrate with a recess 12 formed on its upper surface. A polymer piezoelectric film 13 having electrodes on both sides is pasted on this substrate 11, and an insulating protective sheet 14 is arranged on this polymer piezoelectric film 13. has been done.

An appearance panel thin plate 15 made of a synthetic resin or metal having spring properties is arranged on the protective sheet 14, and an upwardly extruded portion 16 is formed in this thin plate 15.

When this extrusion part 16 is pressed with a fingertip or the like, it reverses from the initial shape shown in the figure to a substantially symmetrical shape, applies stress to the polymer piezoelectric film 13, displaces it, and generates an electric signal from the polymer piezoelectric film 13.

Then, when the pressing force of the extrusion section 16 is released, the extrusion section 16 automatically reverses itself and returns to its original state due to its own elasticity.

Further, on the upper surface of this extrusion part 16, letters, numbers,
Indications 17 such as symbols can be formed by printing, etching, or the like.

Note that FIG. 4 shows a single piece of polymer piezoelectric film 13.
The structure is such that a plurality of unit piezoelectric elements are scattered by adding some ingenuity to the formation of the electrodes, and the number of recesses 12 in the substrate 11 is also provided to correspond to the unit piezoelectric elements, and the outer panel thin plate 15 also corresponds to the unit voltage elements. Extrusion section 1
6 is used as a keyboard.

Since the piezoelectric switch of the present invention is constructed as described above, it is possible to make it extremely thin and reduce costs by simply fixing a polymer piezoelectric film, a protective sheet, and a thin exterior panel on the substrate. In addition, since the reversal is performed at the extruded part of the thin spring-like exterior panel, it is possible to control the operation, making it easy to operate and output stable electrical signals.Moreover, the display is also on the thin exterior panel. It has the advantage of being easy to carry out, and has great practical value.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of a conventional piezoelectric switch, Figure 2 is a cross-sectional view of a conventional piezoelectric switch.
This figure is a sectional view of another conventional piezoelectric switch, FIG. 3 is a sectional view showing an embodiment of the piezoelectric switch of the present invention, and FIG. 4 is a top view of the same. DESCRIPTION OF SYMBOLS 11... Substrate, 12... Recessed part, 13... Polymer piezoelectric film, 14... Protective sheet, 15... Thin plate, 16... Extruded part, 17... Display.

Claims (1)

[Claims for Utility Model Registration] (1) A method of obtaining electrical signals from a polymer piezoelectric film by applying stress to the polymer piezoelectric film and displacing the polymer piezoelectric film by using a polymer piezoelectric film having electrodes on both sides. In a piezoelectric switch configured as shown in FIG. A piezoelectric switch configured by arranging. (2) The piezoelectric switch according to claim 1 of the utility model registration claim, which is provided with displays such as letters, numbers, signals, etc. on the upper surface of the extruded portion of the thin plate.